1. Field of the Invention
This invention relates generally to acetylene-terminated oligomers. It relates particularly to a series of phenylethynyl-terminated poly(arylene ethers) which can be thermally cured to resins that are useful as adhesives, composite matrices, and moldings.
2. Description of Related Art
Poly(arylene ethers) are condensation polymers commonly synthesized by nucleophilic displacement of activated aromatic halides in polar solvents by alkali metal phenates to form a repeat unit of the general type ##STR1## wherein Ar is arylene and X is CO, SO.sub.2,
Nucleophilic displacement reactions leading to high molecular weight poly(arylene ethers) were initially reported in 1958 (A. Kreuchumas, U.S. Pat. No. 2,822,351). Since then numerous papers and patents have appeared, such as R. N. Johnson et al., Polym. Sci. A-1, 5, 2375 (1967), S. V. Vinogradova et al., Polym. Sci. USSR, 14, 2963 (1972), J. B. Rose, Polymer, 15, 456 (1974), T. E. Attwood et al., Polym. Prepr., 20(1), 191 (1979), T. E. Attwood et al., Polymer, 22 1096 (1981), R. Viswanathan et al., Polymer, 25, 1927 (1984), P. M. Hergenrother et al., Polymer, 29, 258 (1988), M. E. B. Jones, British Patent No. 1,016,245, H. A. Vogal, British Pat. No. 1,060,546, I. Goodman et al., British Patent No. 971,277 (1964), A. G. Farnham et al., British Patent No. 1,078,234, and A. G. Farnham, U.S. Pat. No. 4,175,175. Poly(arylene ethers) are known for their good mechanical properties, good thermooxidative stability and relative ease of processing. Several poly(arylene ethers) such as Udel.RTM. polysulfone (Amoco), Kadel.RTM. polyketone (Amoco), PEEK.RTM. polyetheretherketone (ICI) and Victrex.RTM. PES polyethersulfone (ICI) are commercially available and used as films, moldings, adhesives and composite matrices.
The majority of poly(arylene ethers) are amorphous and are therefore soluble in common organic solvents. Those poly(arylene ethers) that are semicrystalline are typically insoluble in these solvents. Certain applications, such as adhesives or composite matrices on commercial or military aircraft, require resistance to aircraft fluids (jet fuel, hydraulic fluid, etc.) and paint strippers as well as temperature cycling. To make poly(arylene ethers) more desirable for use in these applications, ethynyl and substituted ethynyl groups have been incorporated into the polymer by a variety of methods to produce thermosetting materials. A review of acetylene-terminated prepolymers has been published by P. M. Hergenrother, in H. Mark, ed. Encycl. Polym. Sci. Engr., 2nd ed., Vol. 1, John Wiley & Sons, Inc., New York, 61 (1985).